patternjavaMinor
Armstrong numbers in a given range using Java 8
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armstrongrangenumbersjavausinggiven
Problem
Was fiddling with java-8; trying to write a program for getting all Armstrong Numbers between
Following is my working solution:
Output:
Why I'm here:
Here is a link to a list of Armstrong Numbers for verifying the outputs.
Please note that there is a follow up question.
1 and 10_000_000.Following is my working solution:
public class ArmstrongNumbers {
public static void main(String[] args) {
IntStream.range(1, 10_000_000)
.filter((n) -> {
int c = 0, temp = n;
while (temp > 0) {
c += Math.pow(temp % 10, Integer.toString(n).length());
temp /= 10;
}
return c == n;
}).forEach(System.out::println);
}
}Output:
1
2
3
4
5
6
7
8
9
153
370
371
407
1634
8208
9474
54748
92727
93084
548834
1741725
4210818
9800817
9926315Why I'm here:
- Can this be made shorter?
- Can any other Java 8 concept be used here?
- Can the use of the
whileloop be avoided and a stream be used somehow (given that it is more elegant)?
- Review overall correctness
Here is a link to a list of Armstrong Numbers for verifying the outputs.
Please note that there is a follow up question.
Solution
Integer.toString(n).length() can be assigned to its own variable.If you wanted to stream the while loop, I suppose you could split a
toString() version of the number via toCharArray() and then calculate the value for each digit individually, then summing the result via the sum function.I don't know whether that'd qualify as "more elegant", though. You would get rid of
c and temp as variables by doing that.Context
StackExchange Code Review Q#134701, answer score: 3
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